Door structure for large freezer

ABSTRACT

For use with a walk-in type refrigerator or freezer, a door structure comprising a frame bounding at least the rectilinear sides of the opening and a door for closing the opening. The frame includes, for each side of the opening, an outer skin providing a longitudinally and inwardly extending first flange, an inner skin providing a longitudinally and outwardly extending second flange parallel to the first flange, and a jamb trim plate disposed between and engaging the flanges. The trim plate includes a longitudinally extending outer portion parallel to and engaging the first flange, a longitudinally extending inner portion parallel to and engaging the second flange, and an intermediate portion perpendicular to and connecting the outer and inner portions. The said intermediate portion provides a longitudinally extending and outwardly facing gasket mounting surface, and it may be provided with a longitudinally extending, laterally narrow slot intermediate its side edges for receivably engaging a projecting portion of a gasket. The door, of course, closes against the gasket. Further, heater strips are mounted on the door to extend longitudinally along the edge portions thereof to bear against the gasket extending about the opening in the frame when the door is closed.

United States Patent [191 Thomas 1 Mar. 11,1975

[73] Assignee: Elliott-Williams Company, Inc.,

Indianapolis, Ind.

[22] Filed: May 20, 1974 [21] Appl. No.: 471,199

John M. Thomas, Indianapolis, Ind.

[52] US. Cl 62/275, 62/440, 292/2515, 49/477, 49/478 [51] Int. Cl. F25d 21/06 [58] Field of Search 62/275, 440, DIG. 14; 292/2515; 49/477, 478

[56] References Cited UNITED STATES PATENTS 2,603,843 7/1952 Hill 49/478 2,659,118 11/1953 Anderson 16/55 3,038,319 6/1962 Kesling 62/275 3,055,193 9/1962 Smith 62/275 3,078,134 2/1963 Haynes 292/2515 3,359,053 12/1967 Hagersdorn 1. 49/478 3,634,971 l/l972 Kesling 49/478 Primary ExaminerWilliam J. Wye Attorney, Agent, or FirmWilliam R. Coffey [57] ABSTRACT For use with a walk-in type refrigerator or freezer, a door structure comprising a frame bounding at least the rectilinear sides of the opening and a door for closing the opening. The frame includes, for each side of the opening, an outer skin providing a longitudinally and inwardly extending first flange, an inner skin providing a longitudinally and outwardly extending second flange parallel to the first flange, and a jamb trim plate disposed between and engaging the flanges. The trim plate includes a longitudinally extending outer portion parallel to and engaging the first flange, a longitudinally extending inner portion parallel to and engaging the second flange, and an intermediate portion perpendicular to and connecting the outer and inner portions. The said intermediate portion provides a longitudinally extending and outwardly facing gasket mounting surface, and it may be provided with a longitudinally extending, laterally narrow slot intermediate its side edges for receivably engaging a projecting por tion of a gasket. The door, of course, closes against the gasket. Further, heater strips are mounted on the door to extend longitudinally along the edge portions thereof to bear against the gasket extending about the opening in the frame when the door is closed.

10 Claims, 5 Drawing Figures DOOR STRUCTURE FOR LARGE FREEZER The present invention relates to large freezers or refrigerators of the walk-in type, and more particularly to the provision of door structures for such systems.

All sorts of door structures have been suggested and are actually being used in such refrigeration systems. The door structure of the present invention is believed to constitute a very advantageous improvement over existing door structures.

First of all, I have provided a door structure or means providing a rectangular access opening comprising frame means bounding at least the sides of the opening and door means for closing the opening, the frame means having a unique and advantageous structure including a unique gasket and gasket mounting structure and the door means including heater strip means extending along the edge portions thereof to bear against the sealing gasket extending about the opening in the frame.

l believe it is novel and very advantageous to provide the heater strip mounted on the door itself in a position such that it will bear against and extend longitudinally along the sealing gasket when the door is closed. The heater means, which serves the purpose of stopping sweating around the access opening, heats the exposed exterior metal surfaces of the door and heats the gasket by conduction to prevent condensation and/or frost from forming there. Particularly, I have put the heater strip means at the weakest thermal point in the system, i.e., at the point where the door closes against the gasket where thermal conduction is the greatest and where an air leak, if it is going to occur, will occur. As will be discussed hereinafter, I prefer to use a magnetic strip within the gasket which is attracted to a metal cover on the heater strip means to perfect the seal between the gasket and cover. The gasket is flexible enough to be pulled by the magnet against the cover. This action in combination with spring forces or spring and cam forces which urge the door closed provides a very tight seal between the door and frame.

In my preferred system, the frame means bounds at least the rectilinear vertical sides, and preferably the rectilinear top, of the access opening, the frame means including, for each side and top of the opening, an outer skin providing a longitudinally and inwardly extending first flange, an inner skin providing a longitudinally and outwardly extending second flange parallel to the first flange and offset from the first flange toward the opposite side or bottom of the opening, and an extruded plastic jamb trim plate disposed between and engaging the flanges. The outer and inner skins are preferably sheet metal and may be any other vapor barrier material. The trim plate may preferably be extruded from a rigid polyvinylchloride (PVC) material. The jamb trim plate preferably includes a longitudinally extending outer portion parallel to and engaging the, first flange, a longitudinally extending inner portion parallel to and engaging the second flange, and an intermediate portion perpendicular to and connecting the outer and inner portions, the intermediate portion providing a longitudinally extending and outwardly facing gasket mounting surface. In the illustrative embodiment, the outer portion provides a longitudinally extending resilient clip portion receivably engaging the first flange while the inner portion provides a similar clip portion receivably engaging the second flange.

Further, in the illustrative embodiment, the intermediate portion also provides, intermediate its edges, a longitudinally extending, laterally narrow slot. A gasket is mounted on the mounting surface provided by the in termediate portion to extend longitudinally therealong, the gasket including a longitudinally extending and inwardly projecting portion engaging into the slot to secure the gasket to the mounting surface. The door, of course, closes against the gasket and, as discussed above, includes heater strip means extending longitudinally along the edge portions thereof to bear against the gasket.

Other objects and advantageous features of the present invention will become apparent as this description progresses.

To the accomplishment of the above and related objects, this invention may be embodied in the form illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that change may be made in the specific construction illustrated and described, so long as the scope of the appended claims is not violated.

In the drawings:

FIG. 1 is a sort of diagrammatical drawing showing, by horizontal section, the frame means and door means of the present invention;

FIG. 2 is an enlarged and fragmentary sectional view ofa portion of the door frame taken generally along the lines 2-2 in FIG. 4;

FIG. -3 is a view similar to FIG. 2 except that it shows the edge of the door closed against the frame portion and squeezing the gasket;

FIG. 4 is a view, greatly reduced in scale, of the wall frame section providing the access opening; and

FIG. 5 is an enlarged cross sectional view of the preferred gasket.

Referring now particularly to the drawings, it will be seen that I have shown a door frame section 10 (FIG. 4) having a top section 12, and left and right side sections l4, 16 which define, with the floor, a rectangular access opening 18. That opening is closed by a rectangular door 20 (FIGS. 1 and 3). My preferred door 20 is a sheet metal shell door filled with foamed plastic insulation material. The illustrative door 20 includes a door outer skin 22 which is formed to provide the side sections as indicated at 24 (FIG. 3) and also an inturned flange 26 extending about the interior of the door. The inner skin 28 of the door is rectangularly shaped and fits within the rectangular frame defined by the in-turned flanges 26. Preferably, as indicated generally at 30 in FIG. 3, there is a space or gap between the outer door skin 20 and inner door skin 28 to provide a thermal barrier. The interior space of the door may be filled with foamed plastic insulation material such as indicated at 32 in FIG. 3. In FIG. 4, I show hinge mounts 36 for the door 20 and in FIG. 1 I show a typical hinge 38.

Turning particularly to FIGS. 2 and 3, it will be seen that the illustrative door frame side section includes an outer skin 44 formed to provide a first flange 46 extending longitudinally along the side and inwardly, an inner skin 48 formed to provide a second flange 50 extending longitudinally along the side and outwardly and parallel to the first flange 46. It will be seen that the flange 50 is offset relative to the flange 46 toward the opposite side of the opening 18. The sectional view of FIG. 2 is taken along the line 2--2 in FIG. 4 to show the jamb trim plate. The opposite side edges of the skins 44, 46 may also be provided with flanges 46, 50 as shown in FIG. 1. Extending between these flanges 46, 50 may be a plastic plate such as indicated at 54.

The extruded plastic jamb trim plate 60 extending between the flanges 46, 50 includes a longitudinally extending outer portion 62 parallel to and engaging the flange 46, a longitudinally extending inner portion 64 parallel to and engaging the flange 50, and an intermediate portion 66 perpendicular to and connecting the outer and inner portions. The intermediate portion 66 provides a longitudinally extending and outwardly facing gasket mounting surface. It will be seen that the illustrative outer portion 62 provides a resilient, longitudinally extending clip portion 68 which receivably engages the flange 46 while the inner portion 64 also provides such a longitudinally extending resilient clip portion 70 which engages the flange 50. The intermediate portion 66 is provided, intermediate its lateral edges, with a longitudinally extending, laterally narrow slot 72 and a box-like rectangular connecting section 74 behind the slot.

After the outer and inner skins 44, 48, jamb trim plate 60 and spanner plate 54 are assembled to provide the door frame section as shown in FIG. 4, the spaces between the outer and inner skins are filled with foamed in place plastic insulation indicated generally at 76. The resultant structure is, therefore, an integral one-piece jamb or frame structure which is structurally sound, neat in appearance and of the proper thermal barrier characteristics.

The gasket which extends along the intermediate portion 66 ofthe trim plate 60 is indicated generally by the reference numeral 80. Turning particularly to FIG. 5, it will be seen that the gasket is extruded to have, in its free or disassembled condition, a generally flat, longitudinally extending base portion 82 from the center of which projects the portion 84 which snaps into or engages into the slot 72. The gasket 80 is also formed to have, at each of the lateral edges of the base portion 82, an inwardly and longitudinally extending projection 86, 88 which engages the gasket mounting surface as shown in FIGS. 2 and 3. Because of the projections 86, 88 the base portion 82, when assembled to the intermediate portion 66, is not flat and is somewhat concave in cross section.

The gasket 80 is also formed to have an outer web portion 92 extending longitudinally and from side to side of the base portion 82 and forming, with the base portion a longitudinally extending chamber 93. As best seen in FIG. 5, this outer web portion 92 is also formed with an intermediate web section 94 which is rectangular in cross section and which provides a longitudinally extending passageway 96 which receives a magnetic strip 98 for holding the door closed.

Referring particularly to FIG. 3, it will be seen that l have shown heater strip means which bears against the gasket 80 and which extends longitudinally along the gasket, the illustrative heater strip means including a channel strip 106 rigidly secured to the inner side of the door 20 preferably to span the gap 30. The channel strip may be secured to the door by screws or rivets or other such fastening means not shown. I prefer to place a plastic strip or some type of fibrous strip behind the gap and then attach the channel strip 106 to the door by means of screws (not shown) which extend through the gap and thread into the plastic or fibrous strip. The channel strip 106 has a flat web section against the inner side of the door and opposite side flanges which extend inwardly from the inner side of the door generally toward the gasket when the door is closed. A heater wire 108 is disposed in the channel strip 106 to extend longitudinally therealong. Then, a cover 110 is mounted on the channel strip 106 to extend longitudinallytherealong. The illustrative cover 110 is formed, in cross section, with a central domed cover portion and with laterally inwardly extending side flange portions which engage, respectively, the side flanges of the channel strip to secure the cover on the channel strip. After the channel strip 106 is secured to the door and the wire is placed therein, the cover 110 may be slid longitudinally over the channel strip or snapped over the channel strip.

As shown in FIG. 3, the heater strip bears directly against the central portion of the gasket 80 and actually deflects the gasket generally to the proportion shown. When the gasket 80 is so deflected, its outer web portion 96a contacts the surfaces of the door 20 to provide a proper air seal. The door 20 may be yieldably urged to its closing position, for instance, by springs or a combination of springs and cams (not shown) incorporated into the hinges 38 which support the door. Further, the magnet 98 will be attracted to the cover 110 of the heater to keep the door 20 closed and to keep the gasket 80 against the cover 110 of the heater. Thus, the combination of the forces urging the door closed against the gasket 80 and the magnetic strip attraction to the cover 110 provides a very tight air seal. The gasket 80 is soft enough or flexible enough to permit the magnetic strip to pull the gasket outwardly toward the cover 110.

The structure of the frame 10 is thermally correct in that the metal skins 44, 48 are separated by the plastic jamb plate 60 and divider plate 54 and by the foamedin-place insulation 76. The thickness of the frame wall section may be, for instance, more than 3 /2 inches such that there is a considerable thermal barrier between the skins 44, 48. For illustrative purposes, the overall dimensions of the jamb trim plate 60, in cross section, may be 3.437 inches between the distal edge of the first flange portion 62 and the distal edge of the second flange portion 64 with the lateral width of the intermediate portion 66 being 1.250 inches. The first flange 62 may be 2.468 inches wide while the second flange 64 may be 0.969 inch wide. The door 20, therefore, may be approximately 2 inches thick. The gasket 80 may have a free or uncompressed width of 1.125 inch and depth of 0.375 inch from the bottom of its base portion 82 to the top or outermost portion against which the heater .cover 110 bears.

The gasket 80 and the structure by which it is connected and disconnected to the gasket mounting surface or intermediate portion 66 is very advantageous. The gasket can be replaced in the field quite easily without special tools. The projecting portion 84 which is in the form of an arrowhead will snap into the slot 72 rather easily securely to attach the gasket to the jamb trim plate 60. Further, with the gasket 80 in the position shown in FIGS. 2 and 3, the gasket is not in a position such that it will be abused by traffic through the opening 18. In other words, the gasket 80 is protected largely by the second flange 64 of the trim plate 60. The door 20 itself does not strike against metal such that the metal skins 22, 28 of the door are protected.

Finally, and again, the placement of the heater strip so that it bears against the gasket is very advantageous because it serves to warm by conduction the outer surfaces 22 and 44 which otherwise would be chilled by conduction which could, under certain conditions of 5 temperature and humidity, cause condensation and/or frost, and to heat the air if it leaks out past the heater and gasket so that it will not form frost on the exterior surfaces about the frame ofthe door. The heater, therefore, is at the weakest thermal point, i.e., where the door closes against the gasket. The heater, of course, is constructed such that the cover 110 can be removed from the channel strip 106 to repair the heater wire 108 without tools.

I claim:

1. In a refrigeration system, means providing a rectangular access opening comprising frame means bounding at least the sides of said opening and door means for closing said opening, said frame means including, for each side of said opening, an outer skin providing a longitudinally and inwardly extending first flange, an inner skin providing a longitudinally and outwardly extending second flange parallel to said first flange, said second flange being offset from said first flange toward the opposite side of said opening, a jamb trim plate disposed between and engaging said flanges, said trim plate including a longitudinally extending outer portion parallel to and engaging said first flange, a longitudinally extending inner portion parallel to and engaging said second flange, and an intermediate portion perpendicular to and connecting said outer and inner portions, said intermediate portion providing a longitudinally extending and outwardly facing gasket mounting surface, said outer portion providing a longitudinally extending clip portion receivably engaging said first flange, said inner portion providing a longitudinally extending clip portion receivably engaging said second flange, and said intermediate portion also pro viding, intermediate its edges, a longitudinally extending, laterally narrow slot, and a gasket mounted on said mounting surface to extend longitudinally therealong, said gasket including a longitudinally extending and inwardly projecting portion engaging into said slot to secure said gasket to said mounting surface, said door means being proportioned and mounted to close against said gasket.

2. [n a refrigeration system, means providing a rectangular access opening comprising frame means bounding at least the sides of said opening and door means for closing said opening, said frame means including, for each side of said opening, an outer skin providing a longitudinally and inwardly extending first flange, an inner skin providing a longitudinally and outwardly extending second flange parallel to said first flange, said second flange being offset from said first flange toward the opposite side of said opening, ajamb trim plate disposed between and engaging said flanges, said trim plate including a longitudinally extending outer portion parallel to and engaging said first flange, a longitudinally extending inner portion parallel to and engaging said second flange, and an intermediate portion perpendicular to and connecting said outer and inner portions, said intermediate portion providing a longitudinally extending and outwardly facing gasket mounting surface, a gasket mounted against and extending longitudinally along said surface, and said door means including heater strip means extending longitudinally along the edge portions thereof to bear against said gasket when said door means is closed.

3. The system of claim 1 in which said door means includes heater strip means extending longitudinally along the edge portions thereof to bear against said gasket when said door means is closed.

4. The system of claim 3 in which said heater strip means includes a channel strip secured to the inner side of said door means to extend along the edge portions thereof, said channel strip having a web section against said inner side and opposite side flanges extending inwardly from said inner side generally toward said gasket when said door means is closed, a heater wire disposed in said channel strip to extend longitudinally therealong, and a cover mounted on said channel strip and extending longitudinally therealong.

5. The system of claim 4 in which said cover is formed, in cross section, with a central domed cover portion and side flange portions which engage the side flanges of the channel strip to secure the cover on the channel strip.

6. The system of claim 2 in which said heater strip means includes a channel strip secured to the inner side of said door means to extend along the edge portions thereof, said channel strip having a web section against said inner side and opposite side flanges extending inwardly from said inner side generally toward said gasket when said door means is closed, a heater wire disposed in said channel strip to extend longitudinally therealong, and a cover mounted on said channel strip and extending longitudinally therealong.

7. The system of claim 6 in which said cover is formed, in cross section, with a central domed cover portion and side flange portions which engage the side flanges of the channel strip to secure the cover on the channel strip.

8. The system of claim 1 in which said gasket is formed to have a generally flat longitudinally extending base portion, said projecting portion for engaging said slot being generally centered in said base portion, said gasket having, at each of the lateral edges of said base portion, an inwardly and longitudinally extending projection which engages the gasket mounting surface, said gasket also having an outer web portion extending longitudinally and from side to side of the base portion and forming, with said base portion, a longitudinally extending chamber.

9. The system of claim 8 in which said outer web portion is formed to provide a longitudinally extending passageway in said chamber for receiving a magnetic strip.

10. The system of claim 9 in which said door means includes heater strip means extending longitudinally along the edge portions thereof to bear against said gasket when said door means is closed, said heater strip means including a metal cover attracted to said mag netic strip. 

1. In a refrigeration system, means providing a rectangular access opening comprising frame means bounding at least the sides of said opening and door means for closing said opening, said frame means including, for each side of said opening, an outer skin providing a longitudinally and inwardly extending first flange, an inner skin providing a longitudinally and outwardly extending second flange parallel to said first flange, said second flange being offset from said first flange toward the opposite side of said opening, a jamb trim plate disposed between and engaging said flanges, said trim plate including a longitudinally extending outer portion parallel to and engaging said first flange, a longitudinally extending inner portion parallel to and engaging said second flange, and an intermediate portion perpendicular to and connecting said outer and inner portions, said intermediate portion providing a longitudinally extending and outwardly facing gasket mounting surface, said outer portion providing a longitudinally extending clip portion receivably engaging said first flange, said inner portion providing a longitudinally extending clip portion receivably engaging said second flange, and said intermediate portion also providing, intermediate its edges, a longitudinally extending, laterally narrow slot, and a gasket mounted on said mounting surface to extend longitudinally therealong, said gasket including a longitudinally extending and inwardly projecting portion engaging into said slot to secure said gasket to said mounting surface, said door means being proportioned and mounted to close against said gasket.
 2. In a refrigeration system, means providing a rectangular access opening comprising frame means bounding at least the sides of said opening and door means for closing said opening, said frame means including, for each side of said opening, an outer skin providing a longitudinally and inwardly extending first flange, an inner skin providing a longitudinally and outwardly extending second flange parallel to said first flange, said second flange being offset from said first flange toward the opposite side of said opening, a jamb trim plate disposed between and engaging said flanges, said trim plate including a longitudinally extending outer portion parallel to and engaging said first flange, a longitudinally extending inner portion parallel to and engaging said second flange, and an intermediate portion perpendicular to and connecting said outer and inner portions, said intermediate portion providing a longitudinally extending and outwardly facing gasket mounting surface, a gasket mounted against and extending longitudinally along said surface, and said door means including heater strip means extending longitudinally along the edge portions thereof to bear against said gasket when said door means is closed.
 2. In a refrigeration system, means providing a rectangular access opening comprising frame means bounding at least the sides of said opening and door means for closing said opening, said frame means including, for each side of said opening, an outer skin providing a longitudinally and inwardly extending first flange, an inner skin providing a longitudinally and outwardly extending second flange parallel to said first flange, said second flange being offset from said first flange toward the opposite side of said opening, a jamb trim plate disposed between and engaging said flanges, said trim plate including a longitudinally extending outer portion parallel to and engaging said first flange, a longitudinally extending inner portion parallel to and engaging said second flange, and an intermediate portion perpendicular to and connecting said outer and inner portions, said intermediate portion providing a longitudinally extending and outwardly facing gasket mounting surface, a gasket mounted against and extending longitudinally along said surface, and said door means including heater strip means extending longitudinally along the edge portions thereof to bear against said gasket when said door means is closed.
 3. The system of claim 1 in which said door means includes heater strip means extending longitudinally along the edge portions thereof to bear against said gasket when said door means is closed.
 4. The system of claim 3 in which said heater strip means includes a channel strip secured to the inner side of said door means to extend along the edge portions thereof, said channel strip having a web section against said inner side and opposite side flanges exteNding inwardly from said inner side generally toward said gasket when said door means is closed, a heater wire disposed in said channel strip to extend longitudinally therealong, and a cover mounted on said channel strip and extending longitudinally therealong.
 5. The system of claim 4 in which said cover is formed, in cross section, with a central domed cover portion and side flange portions which engage the side flanges of the channel strip to secure the cover on the channel strip.
 6. The system of claim 2 in which said heater strip means includes a channel strip secured to the inner side of said door means to extend along the edge portions thereof, said channel strip having a web section against said inner side and opposite side flanges extending inwardly from said inner side generally toward said gasket when said door means is closed, a heater wire disposed in said channel strip to extend longitudinally therealong, and a cover mounted on said channel strip and extending longitudinally therealong.
 7. The system of claim 6 in which said cover is formed, in cross section, with a central domed cover portion and side flange portions which engage the side flanges of the channel strip to secure the cover on the channel strip.
 8. The system of claim 1 in which said gasket is formed to have a generally flat longitudinally extending base portion, said projecting portion for engaging said slot being generally centered in said base portion, said gasket having, at each of the lateral edges of said base portion, an inwardly and longitudinally extending projection which engages the gasket mounting surface, said gasket also having an outer web portion extending longitudinally and from side to side of the base portion and forming, with said base portion, a longitudinally extending chamber.
 9. The system of claim 8 in which said outer web portion is formed to provide a longitudinally extending passageway in said chamber for receiving a magnetic strip. 